Physio-chemical Changes Occurring During the Dehydration of Yellow European Plums (Prunus domestica L.) into Golden-dried Prunes
Fresh and dried plums are a rich source of various vitamins, minerals, and phytochemicals. The newly developed variety of Yellow European plums (YEPs) (Prunus domestica L.) at Vineland Research and Innovation Centre, University of Guelph exhibits superior nutritional properties as compared to traditional prune-making plums. Drying of plums to prunes plays a significant role in governing the quality of the final product. While drying enhances the value of the food products, it is an energy demanding process. In the present study, conventional (hot-air) and advanced (freeze-drying) methods were optimized with and without chemical pre-treatments and their effect on the nutritional and functional quality of YEPs was investigated. Corresponding drying characteristics were determined by fitting the moisture ratio curves obtained for each YEP genotypes with various drying kinetic models. In addition, utilization of chemical pre-treatment prior to drying resulted in an increase of the drying rate and reduction of drying time, making the process more cost and energy efficient. The effect of drying conditions on the quality of the product was evaluated based on color, total phenolic content and antioxidant activity. It was also observed that drying method significantly affects the physical and chemical characteristics during the development of “golden prunes”.